1. Field of the Invention
The invention relates to the field of image processing with a view to the automatic detection of the horizon that appears in these images.
The automatic detection of the horizon is a determining factor in certain applications, such as surveillance systems, piloting assistance, target-detection assistance, etc.
2. Description of the Related Art
Among known detection methods, te may distinguish methods fo the preparation of artificial horizons and methods for the detection of the horizon in an image from a video signal delivered by a camera. The former methods are based on a positional and directional locating of the aircraft by means of an inertial unit, and the latter are based on image processing systems that use different attributes or parameters characteristic of the horizon (for example, the study of the luminance gradients).
The known methods lack precision, both in the plane of the spatial localization and in that of the temporal determination. For the first category of methods, the determination of the horizon is absolute, without taking account of the true relief, for it is used only to define the trim of the aircraft. For the second category of methods, the lack of precision is expressed by a high degree of noise which may even result in the providing of an aberrant element of information.